B-group vitamin deficiency in cultured herring

A mortality of cultured herring caused by vitamin B deficiency was successfully treated with yeast extract (‘Marmite’) with added vitamin B₆. The supplementation to the diet comprised approximately Riboflavin 0.21 mg, Niacin 2.33 mg and Pyridoxine (B₆) 0.6 mg, all per kg wet-weight of fish per day.     

Fatty acids and egg quality in great scallop

Spawners of the great scallop, Pecten moximus, were conditioned on three microalgal diets: T-Isochrysis, a mixture of four species (PTSC) and Chaetoceros calcitrans.The polyunsaturated fatty acid (PUFA) composition of neutral and polar lipids of eggs was related to the fatty acid composition of the diet. However, the 20 and 22 carbon PUFAs were maintained at significant levels independent of those of the diet when these fatty acids were present in the diet at low levels. This effect was more pronounced in the polar than in the neutral lipids. A preferential incorporation of 22:6(-3) and 20:4(-6) was demonstrated in the polar lipids. This emphasizes their role in ovogenesis and embryogenesis.The 22:6(-3) requirement of P. maximus was better satisfied by T-Isochrysis, which favoured the highest incorporation of this essential fatty acid in the eggs. The good success in reproduction obtained with this monospecies diet led us to modify multispecies diets by increasing the level of 22:6(-3).     

Oxidative stability of salmon and herring roe lipids and their dietary effect on plasma cholesterol levels of rats

ABSTRACT:   The oxidative stability of lipids from salmon roe and herring roe was compared with those of commercial fish oils originated from sardine and tuna. Both fish roe lipids contained high amounts of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Total EPA and DHA was more than 35% of total fatty acids in both roe lipids. On the basis of oxygen consumption, fish roe lipids showed the higher oxidative stability than both fish oils. This tendency in oxidative stabilities was also confirmed by the determination of propanal formation during oxidation. Analyses of lipid compositions suggested that the higher oxidative stabilities of fish roe lipids would be mainly due to the presence of phospholipids in them. Dietary effects of salmon and herring roe lipids were also determined. Little increase in total cholesterol level was observed in plasma lipids in rats fed salmon and herring roe lipids, although cholesterol content in fish roe lipids were 6.3% and 9.7% of total lipids for salmon roe and herring roe.     

氯化钴在大菱鲆饲料中的安全性评价

不同鱼类的脂肪组织分布模式具有高度多样性。大菱鲆具有相对特殊的脂质储存模式;鳍条附近皮下脂肪组织是其重要的脂肪存储部位。为了更好地了解大菱鲆的脂质代谢生理,本实验初步研究了29个脂质代谢相关基因在大菱鲆体内的组织表达,这些基因参与了脂肪生成、脂肪酸β氧化、甘油酯的生物合成和水解、脂质运输以及相关的脂代谢转录调控过程。从30尾鱼(10尾混样作为一个重复)中采集眼、鳃、脑、皮肤、肌肉、肝脏、胃、肾脏、脾脏、心脏、前肠、幽门盲囊、后肠、盲肠和脂肪等共15个组织样本进行qRT-PCR分析。结果显示,肠和脑中脂肪生成基因表达量高,肝脏和肌肉脂肪生成基因表达量低。肠内大部分载脂蛋白和脂质代谢相关转录因子的基因表达水平也较高。肌肉中脂肪酸β氧化相关基因的表达水平较低。细胞内甘油酯酶在脑、眼和心脏中高表达。研究表明,在大菱鲆体内,肠道可能不仅是脂质摄取的场所,也是大菱鲆体内重要的脂肪代谢器官。本研究为进一步探讨大菱鲆脂代谢特征及探索不同储脂类型鱼类中脂肪代谢的多样性提供了基础数据,也将有助于在分子水平上进一步研究鱼类的脂质代谢调节。

     

冬、夏季6种经济贝类脂肪酸组成

测定和比较了广东湛江地区6种常见经济贝类冬、夏季19种主要脂肪酸组成,探讨了冬、夏2季气候变化对贝类脂肪酸组成的影响和相应的脂肪酸营养价值.结果表明,检测的6种海洋贝类冬、夏季总脂含量分别为(0.11±0.01)%～(0.19±0.01)%,(0.15±0.00)%～(0.45±0.04)%;饱和脂肪酸(SFA)分别为35.15%～47.29%,41.96%～45.99%;单不饱和脂肪酸(MUFA)分别为9.47%～17.68%,13.62%～18.04%;多不饱和脂肪酸(PUFA)分别为39.35%～48.56%,36.25%～43.15%.通过方差分析,6种贝类冬季SFA、MUFA和PUFA的含量均比夏季高,且具有显著差异;冬季的总脂含量虽然比夏季高,但差异不显著.     

太平洋鲱和大西洋鲱间的形态变异研究

为阐明太平洋鲱和大西洋鲱种间形态上的差异,应用单因子方差分析、聚类分析和判别分析方法对两种鱼的23个形态学参数进行了研究。单因子方差分析结果表明：14个形态参数平均值存在极显著差异（P〈0．001）,且种群间差异大于种内差异。聚类分析结果显示所有82个个体明显聚成两支。所有23个形态参数的判别分析结果表明,两种间的形态差异极显著（P〈0．001）;利用挑选后的11项参数判别分析,得出判别等式,两种鱼间的形态差异仍然极显著（P〈0．001）,判别准确率100％。所有23个形态参数的差异系数全部小于Mayr的75％法则临界值,表明两个种间形态学上虽然存在一定分化,但分化程度尚未达到亚种水平。作者推测两个种间形态上低水平的分化可能由于分化的时间较短以及相似的生活环境造成的。     

Sperm-activating proteins obtained from the herring eggs

Spermatozoa of the Pacific herring, Clupea pallasii, were immotile in a solution of isotonic to seminal plasma, but swimming was initiated in a hypertonic solution such as 60% water. The motility of herring spermatozoa became active in the presence of freshly ovulated eggs, suggesting that ovulated eggs release the sperm-activating proteins, which are prerequisite to successful fertilization. Five species of herring sperm-activating proteins (HSAP) with different pI values (4.8, 4.9, 5.0, 5.1 and 5.4) were purified from the egg-conditioned medium by gel filtration and isoelectric focusing. Molecular mass of the HSAP (pI=5.1), the major species of the five HSAPs, was determined to be 8.1 KDa by mass spectrometry. Complementary DNA clones encoding herring sperm-activating proteins were isolated from a herring ovarian complementary DNA library and amino acid sequences were deduced. The herring sperm-activating protein(s) is a secretory product(s) with strong homology to Kazal-type trypsin inhibitors, such as mammalian acrosin inhibitors. The sperm-activating proteins were globally distributed in the outermost layer of the egg chorion and its gene was expressed in the follicle cells that surround developing oocytes. Both HSAPs and HSAP fragment (HSAP-E) could induce the membrane depolarization and increase in the intracellular Ca²⁺ concentration of herring spermatozoa. These results suggest that, in the Pacific herring, trypsin inhibitor like proteins are synthesized in the follicle cells, secreted, accumulated in the egg chorion during oocyte development and released into the milieu at spawning to activate the motility of spermatozoa at the time of gamete interaction.     

Fatty acids in muscle of wild and farmed red porgy, Pagrus pagrus

The total fat content and the fatty acids of total lipids (TL), phospholipids (PL) and triacylglycerols (TAG) were analysed in white muscle from wild and reared red porgy, Pagrus pagrus (L.). The fat percentage was higher in reared (3.03 ± 0.57%) (mean ± SE) than wild (0.65 ± 0.03%) fish. The fatty acid pattern of reared porgy TL reflected the diet's lipid. Wild red porgy showed higher levels of ω3 and ω6 polyunsaturated fatty acids (PUFA) than reared, but both the atherogenic index and the index of thrombogenicity were very low for both wild and reared red porgy. The lipid fractions showed that the PL were composed of very high levels of PUFA, especially 22:6ω3, and their composition seemed to be better regulated than the composition of TAG. TAG showed greater differences between wild and reared fish, presumably because they reflected the dietary content of lipids. PUFA were the principal component of wild red porgy TAG.     

Distribution of lipids and fatty acids in the zooxanthellae and host of the soft coral Sinularia sp.

The lipid classes and the fatty acid (FA) compositions of the zooxanthellae, the host tissue, and intact coral were determined for the first time in a soft coral, Sinularia sp. The contents of monoalkyldiacylglycerol (MADAG), triacylglycerol, and polar lipids differed significantly between the zooxanthellae and the host fractions. The zooxanthellae were rich in polar lipids, whereas neutral lipids were concentrated in the host. MADAG comprised 35% of the host lipids and was practically absent in zooxanthellae. Hence, MADAG is only synthesized in animal tissues and serves as a biomarker for the host in the host–zooxanthellae association of these soft corals. Similar to the zooxanthellae of reef-building corals, the main FA in the zooxanthellae of Sinularia sp. were 18:4n-3, 20:5n-3, and 22:6n-3. In addition, 16:3n-4 and 16:4n-1 (8.9% in total) were found in these zooxanthellae. The ratios of 16:3n-4, 16:4n-1, 18:4n-3, 20:5n-3, and 22:6n-3 in the zooxanthellae to those in the host tissue were 4.2, 11.2, 10.1, 11.0, and 9.1, respectively. The proportions of some FA and lipid classes in the intact coral and its fractions showed that zooxanthellate lipids comprised 36 ± 15% of the total lipids in Sinularia sp. Two tetracosapolyenoic acids (24:5n-6 and 24:6n-3) are proposed as a biomarkers of the animal tissue and indicators of the purity of the zooxanthellae fractions from soft corals.     

Fatty acid compositions in muscles of wild and cultured ocellate puffer Takifugu rubripes

Lipid contents and fatty acid compositions were compared among 110 muscle samples of Japanese wild, Japanese cultured, and Chinese cultured ocellate puffer Takifugu rubripes. The effects of diet on muscle lipids in cultured ocellate puffer were also investigated. There was no noticeable difference between the wild and cultured fish with regard to the lipid content, but there were significant differences in the fatty acid composition ratio such as C16:0, C16:1n-7, and C20:4n-6. Moreover, the percentages of the fatty acids C18:2n-6 and C22:5n-3 were correlated with those in the diet. These results suggest that the muscle lipid content was not affected by diet, whereas fatty acid composition was affected. There were significant differences in fatty acid composition among Japanese wild fish, Japanese cultured fish, and Chinese cultured fish. The results suggest that the fatty acid composition is applicable as a tool to distinguish between wild and cultured ocellate puffer as well as those cultured in Japan and China.     

Fatty acids as trophic biomarkers in vitellogenic females in an impounded tropical river

Fatty acids have been used in marine biogeochemistry as food chain biomarkers, but in freshwater these studies are rare. In order to evaluate the fatty acid potential as biomarkers in freshwater, their profile was analyzed during vitellogenesis in two fish species, in both waterfall and reservoir environments of the Paraíba do Sul River Basin. Detrivorous Hypostomus affinis and omnivorous Geophagus brasiliensis seem to elongate and desaturate polyunsaturated fatty acids (PUFA) and transfer them to the ovaries’ phospholipids. Waterfall Geophagus brasiliensis have more highly unsaturated fatty acids in the liver, but in the reservoir, accumulation mainly occurs in muscle and ovary triglycerides, suggesting trophic opportunism and a plasticity during vitellogenesis. In Hypostomus affinis, PUFA alteration occurs only in the reservoir, suggesting a high phytoplankton occurrence. Eutrophication and water speed is reflected in Hypostomus affinis ovaries by higher PUFAn3 and bacterial fatty acids. As in marine environments, analysis of mono- and polyunsaturated fatty acids during vitellogenesis can be used as a tool in food chain studies in freshwater.     

Growth and kinetics of lipids and fatty acids of the clam Venerupis pullastra during larval development and postlarvae

This study examines the larval development, metamorphosis and postlarval stage of Venerupis pullastra in relation to growth, lipids content and fatty acid composition, specifically those believed to be essential for most bivalves (i.e. 20:5n‐3 and 22:6n‐3). Clam larvae were fed with two species of microalgae supplied individually or mixed –Isochrysis galbana and Tetraselmis suecica–species normally used in bivalve hatcheries. Larvae fed with T. suecica showed a progressive accumulation of lipids and fatty acids but did not survive to metamorphosis. Contrarily, larvae fed with I. galbana or mixed diet showed a progressive decline in lipids and essential fatty acids (20:5n‐3 and 22:6n‐3) from the pediveliger stage onwards, and a survival rate of 95% until the start of metamorphosis. The lower content in n‐6 and the absence of 22:6n‐3 in T. suecica diet might contribute to the massive mortality observed for larvae fed with this diet. That diet seems to fail in the supply of some particular nutrient that allows energetic transformation of reserves for growth and metamorphosis. Nevertheless, larvae fed on mixture diet showed higher weight growth values at postlarval stage than those larvae fed on I. galbana diet.     

Fatty acid and proximate composition of bluefin tuna (Thunnus thynnus) muscle with regard to plasma lipids

The composition of tail muscle fatty acids from wild and cultured bluefin tuna reared on a diet based on herring and sardine, along with the plasma lipid profile of the farmed individuals, was determined. The total lipid content of farmed bluefin in this study was 0.922 g/100 g or 3.49 g of saturated fatty acids (SAFA), 4.48 g of monounsaturated fatty acids (MUFA), 2.58 g polyunsaturated fatty acids (PUFA) n‐3 and 0.37 g of PUFA n‐6 fatty acids; for wild specimens, it was 0.920 g/100 g, or 2.85 g of SAFA, 4.82 g of MUFA, 2.78 g PUFA n‐3 and 0.27 g of PUFA n‐6 fatty acids. The major fatty acids in this study were 16:0; 16:1, n‐7; 18:1, n‐9 and DHA 22:6, n‐3 acids. The sum of these major components accounted for more than 57% and 80% of the total fatty acids in all the samples of farmed and wild tuna respectively. No significant differences in the proximate composition were demonstrated between farmed and wild samples, except for the energy value, in favour of the farmed tuna. Statistically, glucose tends to increase together with cholesterol (CHOL) and plasma triglyceride, as for these pairs, it showed positive correlation coefficients and P>0.05. Some measured tuna metabolites demonstrated strong mutual correlations, especially GLU, CHOL and TRIG, which are crucial factors in the lipid profile of animals.     

Elevation of lipid peroxide level and production of hydroxy lipids in cultured Hepa-T1 cells by oxidative stressors

ABSTRACT:   In order to investigate the relationships between levels of lipid peroxides (LPO), hydroxy lipids (L-OH) and of antioxidative enzymes in live fish, cultured cells from tilapia liver (Hepa-T1) were treated with oxidative stressors, 2,2'-azobios(2-amidino-propane) dihydrochloride (AAPH) and H₂O₂. By treating with 5 mM AAPH, LPO and L-OH of the cells significantly increased time-dependently. In particular, L-OH increased from 7.6 ± 0.7 to 23.6 ± 1.8 nmol/mg protein after 2 h of treatment, and synchronously the glutathione peroxidase (GPx) activity of the cells increased from 259 ± 106 to 1970 ± 135 mU/mg protein. In the case of H₂O₂, however, no elevation of L-OH was observed. In this case, catalase (CAT) and superoxide dismutase (SOD) activities increased time-dependently. Especially, after 2 h exposure, the CAT activity increased remarkably from 217 ± 21 to 2510 ± 120 mU/mg protein, though the GPx activity did not change significantly. These results suggest that the elevation of the L-OH level is closely associated with the elevation of GPx activity, but not with that of CAT or SOD. However, when vitamin E-enriched Hepa-T1 cells were treated with AAPH and H₂O₂, the production of LPO and L-OH was suppressed significantly. The findings suggest that vitamin E also plays an important role in the levels of the oxidation products in vivo .     

Fatty acid and carotenoid composition of eggs from two nonanadromous Atlantic salmon stocks of cultured and wild origin

Two Swedish landlocked (nonanadromous) salmon (Salmo salar) stocks were investigated with the aim of characterising their egg fatty acid (FA) and carotenoid profiles. Fish from one of the stocks were also cultured over the past few decades as part of the Swedish program for genetic preservation, allowing a comparison between the eggs from females on a diet based on lipids of limnic (natural food chain) origin and eggs from females fed an artificial diet of marine origin. No significant differences in the FA profile of the phospholipid (PL) or triacylglycerol (TAG) fraction were found between the two wild stocks. The content of EPA (20:5n-3, eicosapentaenoic acid) in PL fraction was significantly higher in eggs from cultured females (13.0%) compared with eggs from both wild stocks (5.7 and 6.4%). Further, in PL fraction, AA (20:4n-6, arachidonic acid) levels in these eggs were significantly lower (2.4% versus 6.7 and 6.2%). The AA content of the TAG fraction differed greatly between wild (4.4 and 4.9%) and cultured (1.2%) eggs, whereas this fraction showed almost no corresponding difference in EPA content. The level of DHA (22:6n-3, docosahexaenoic acid) did not differ between the two wild stocks or between wild and cultured fish. This was in spite of widely different levels of DHA in the diet. The composition of carotenoids was altered in the cultured eggs which had a higher proportion and higher content (1.16 g egg^–1) of astaxanthin than the wild eggs (0.56 and 0.62 g egg^–1, respectively). Hatching success varied markedly between wild (>95%) and cultured fish (40–75%). We conclude that changes in the lipid source in the diet of female salmon during gonadal maturation will alter the egg fatty acid composition with an increased risk of disturbances in embryonic development as a consequence. Further, the lack of any difference between wild and cultured females in terms of their egg DHA content indicates that there is a strong genetic influence on levels of this fatty acid in salmon eggs.     

Seasonal variations of free amino acids and nucleotide-related compounds in the muscle of cultured Taiwanese puffer Takifugu rubripes

SUMMARY: Seasonal variation in the level of extractive nitrogenous components was investigated in the muscle of puffer Takifugu rubripes cultured in two different areas of Taiwan. There were no seasonal and regional variations in the proximate composition of the fish. Of the free amino acids (FAA) in the muscle of puffer, the predominant one was taurine, followed by glycine, lysine, and alanine. Among nucleotide-related compounds, inosine monophosphate (IMP) and guanosine monophosphate (GMP) were the most prominent compounds. The total nucleotide-related compounds in the muscle of puffer were higher in July and November than those in the other months. The level of total taste-active components including glycine, alanine, arginine, GMP, IMP, and adenosine 5'-monophosphate was much higher in the muscle of puffer collected from July to January. Therefore, the puffer is probably more palatable in these periods.     

封闭循环流水养殖的花鳗鲡脂肪酸特征分析

为探寻封闭循环流水养殖模式下养殖的较大型(≥2 kg)花鳗鲡(Anguilla marmorata)各可食部的脂肪酸特征,利用索氏抽提法获得各部位的粗脂肪,以37种脂肪酸甲酯混标标准品为标准,气相色谱外标法检测脂肪酸的组成。检测结果显示,鱼皮中粗脂肪含量最高为26.96%,鱼肉的粗脂肪含量为10.36%;不同可食部的脂肪酸组成基本相似,饱和脂肪酸9种,单不饱和脂肪酸6种,多不饱和脂肪酸8种,饱和脂肪酸、单不饱和脂肪酸和多不饱和脂肪酸间的比例大约都为1∶3∶1,三大类脂肪酸中含量最高的分别为软脂酸C16∶0、油酸C18∶1n9c和二十二碳六烯酸C22∶6n3,油酸在不同可食部中均超过20 g/100 g总脂,C22∶6n3(DHA)在不同可食部中含量在4.42~5.59 g/100 g总脂之间。研究表明,较大型花鳗鲡是人体所需脂肪酸的良好食物来源。     

The highs and lows of herring: A meta‐analysis of patterns and factors in herring collapse and recovery

Pacific and Atlantic herring populations (genus Clupea) commonly experience episodic collapse and recovery. Recovery time durations are of great importance for the sustainability of fisheries and ecosystems. We collated information from 64 herring populations to characterize herring fluctuations and determine the time scales at low biomass and at high and low recruitment, and use generalized linear models and Random Survival Forests to identify the most important bottom‐up, top‐down and intrinsic factors influencing recovery times. Compared to non‐forage fish taxa, herring decline to lower minima, recover to higher maxima and show larger changes in biomass, implying herring are more prone to booms and busts than non‐forage fish species. Large year classes are more common in herring, but occur infrequently and are uncorrelated among regionally grouped stocks, implying local drivers of high recruitment. Management differs between Pacific and Atlantic herring fisheries, where at similarly low biomass, Pacific fisheries tend to be closed while Atlantic fisheries remain open. This difference had no apparent effect on herring recovery times, which averaged 11 years, although most stocks with longer recovery periods had not yet recovered at the end of the observation period. Biomass recovery is best explained by median recruitment and variability in sea surface height anomalies and sea surface temperatures—higher variability leads to shorter recovery times. In addition, the duration of recruitment failure is closely linked with low biomass. While recovery times rely on the nature of the relationship between spawning biomass and recruitment, they are still largely governed by complex and uncertain processes.